STINK BUGS

(All stages about three times natural size.)

STINK BUGS

Stink bugs attack a wide variety of plants. Several species seriously damage cotton in all areas where cotton is grown. They feed largely on bolls and seldom invade the cotton fields in large numbers until the plants are fruiting. They insert their needlelike beaks into the bolls and suck the juice from the immature seed. The punctures may cause the shedding of young bolls. Small bolls become soft, turn yellowish, and fall off. Punctured bolls not thrown off by the plants may show injury varying from a slight stain in one lock of the mature boll to what is termed an "unpickable" boll or a boll in which every lock has been punctured. Severe injury results in a mummified, prematurely half-opened boll in which the lint in every lock is stained, short, weak, and of little marketable value. If populations are heavy and uncontrolled, the yield might be reduced more than half and the grade of lint and seed lowered greatly.

The southern brown stink bug occurs in all the cotton-growing States as far west as New Mexico. The closely related Arizona brown stink bug attacks cotton in New Mexico, Arizona, and California. The range of the southern green stink bug covers the extreme southern portion of the United States, although at times it occurs north of this area. The most serious damage to cotton has been noted in the Southeastern States. The Say stink bug occurs most abundantly in Texas, Oklahoma, New Mexico, Arizona, and California. The conchuela occurs most often on cotton in Texas and New Mexico.

Control: Stink bugs can be controlled on cotton by dusts containing enough benzene hexachloride to give 3 percent of the gamma isomer plus 5 percent of DDT and 40 percent of sulfur, or sufficient benzene hexachloride to give 2 percent of the gamma isomer plus 10 percent of DDT and 40 percent of sulfur. Also, a dust containing 15 percent of toxaphene plus 5 percent of DDT and 40 percent of sulfur may be used. These dusts should be applied at the rate of 10 to 15 pounds per acre.

Two treatments with sprays made from emulsion concentrates have given effective control: Benzene hexachloride to give 0.4 pound of the gamma isomer per acre; and benzene hexachloride to give 0.3 pound of the gamma isomer plus 0.75 pound of DDT per acre.